1. Field of the Invention
The invention relates to apparatus having means for indicating the number of photographically exposed instant type film units contained within a storage chamber.
2. Description of the Prior Art
The invention relates to apparatus having a chamber for receiving and storing photographically exposed film units until such time that they are to be removed therefrom for processing of their latent images, and more particularly to such an apparatus having a means for indicating the number of exposed film units contained within the chamber.
Lately there has been proposed a system which includes (1) a camera back having a film chamber, for receiving a film cassette containing a stack of premounted transparency film frames of the instant or self-developing type, and a storage chamber, for receiving the film frames subsequent to their exposure, and (2) a processor into which the camera back may be placed for the processing of the individual film frames. This system is described in U.S. Pat. No. 4,568,163, granted to Frank M. Czumak et al. on Feb. 4, 1986. However, there does not appear to be any way in which the user can positively tell how many, if any, photographically exposed film frames are contained within the storage chamber. Thus, valuable time may be lost if the user were to detach the camera back from a camera and insert it into the processor if there were no film frames contained within the storage chamber.
Film counters per se are well known as evidenced by U.S. Pat. Nos. 1,195,187, 3,653,313, and 4,212,524. The '187 patent discloses a camera back having a slot therein and the film is provided with a backing sheet having indicia thereon which is viewable through the slot. The '313 and '524 patents disclose cameras having film counters which are automatically reset to their starting positions upon the removal of a film cassette from the camera's film chamber. As such, the counters do not necessarily give a true reading of the number of film units contained within the cassette. For example, if the starting position of the counter were "10" and two exposures were made thereby indexing the counter into the "8" position, an incorrect reading would occur if the user were to now remove the cassette from the camera and reinsert it, thereby resetting the counter to the "10" position.